Railway signaling system



Feb. 10, 1942.

Fig.1.A.

O .H. DICKE E'I'AL" RAILWAY SIGNALIING SYSTEM Fildfian. 17, 1940 3 Sheets-Sheet l INVENTORS' OH Qicke and FBHiTcHc THEIR ATTORNIZIY Feb. 10, 1942.

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O. H. DICKE ETAL RAILWAY SIGNALING SYSTEM Filed Jan. 17, 1940 5 Sheets-Sheet s l I A A INVENTOR5 I OHDicke and EBHiTchcock THEIR ATTOiRNEY Patented Feb. 10, 1942 RAILWAY SIGNALING SYSTEM Oscar H. Dicke, Rochester, and Forest B. Hitchcock, Greece, N. Y., assignors to General Railway Signal Company, Rochester, N. Y.

Application January 17, 1940, Serial No. 314,260

9 Claims.

The present invention relates to track circuits for absolute-permissive block signaling systems and the system itself, and more particularly to such a system in which undivided blocks are employed between successive signals, and is an improvement over the application of Hoppe, Ser. No. 253,837, filed January 31, 1939. This feature of undivided blocks also permits the ready addition of continuous inductive train control.

An absolute-permissive block signaling system is a system for single track train operation and signaling which affords by signal indication the usual double block protection behind a train moving through a single track section, and which absolutely prevents the entrance of a train in one direction into a single track section when such section has already been occupied by a train moving in the opposite direction. It is the usual practice in absolute-permissive block signaling systems to have a track relay at each end of a block so that there is a track relay at the entrance to the block for each direction of trafiic. If the usual divided block is employed the source of track circuit current is usually located at an intermediate point in the block and feeds current in both directions.

In accordance with the present invention it is proposed to employ an undivided block and to apply pulsating current to opposite ends of the block, each application of current being in a manner and of a polarity depending on traffic conditions in advance in that direction and by applying these currents alternately at a very rapid rate and to connect track relays to opposite ends of the block alternately at the same rapid rate in such a manner that each track relay is energized from a source of current applied to the opposite end of the block but can never be energized by the source of current applied to the same end of the block. This structure not only permits a track relay to be employed at each entrance end of the block for both directions of traflic but it also afiords the employment of a track source to supply current to the exit end of the block for each direction of train travel, which trackway current may be inductively picked up by suitable car carried receiving apparatus located on the front end of the'train moving through such section.

More specifically it is proposed to provide an alternating current transmission line continuously supplied with alternating current of a suitable frequency which in the present instance is assumed to be 60 cycles, although a frequency distinctive from commercial frequencies such as 55 100 cycles or any other suitable frequency may be used if desired. It is also proposed to provide a synchronous vibrator or other suitable synchronous commutating means at the junction between successive blocks which commutating means connects a track relay and a source of alternating or pulsating current to the trackcircuit at that end alternately for both of the two adjacent block ends. These vibrators are preferably so tuned and connected that alternating current is applied by these vibrators to the track circuit at one end, while a track relay is connected to the track circuit at the other end and so that another source of alternating current is connected to the other end of the track circuit while the track relay is connected to the track circuit at that end, these vibrators in the specific arrangement shown commutating the alternating current in a manner so that pulsating current of either plus or minus polarity is applied to one end of the track circuit, during the same half of a cycle of alternating current, while the track relay at the other end is connected to the track circuit. It is further proposed in accordance with the present invention to selectively apply pulsating current of a polarity in accordance with trafiic conditions in advance, and to construct the track relays to be polarity responsive, and it is proposed further to control wayside signals through the medium of these polarity responsive relays. It is also proposed to provide suitable car-carried apparatus inductively coupled with the track circuit ahead of the train together with suitable amplifying circuits on the train for visually indicating on the train conditions of trafiic in advance of the train as reflected by the presence or absence of pulsating current in the track circuit ahead.

Other objects, purposes and characteristic fea tures of the present invention will in part be pointed out hereinafter and is in part obvious from the accompanying drawings.

In the drawings Figs. 1A, 1B and 10, when laid side by side in that order, show a portion of a single track section including two complete blocks and the adjacent ends of two other blocks of railway track equipped with the invention.

Structure Referring to Figs. 1A, 1B and 10, when laid side by side, these drawings illustrate the blocks X and Y and the adjacent ends of two other blocks W and Z. These blocks are electrically separated from each other by insulating joints l2 to form track circuitable track sections. The

entrance end of each block is provided with a signal S. The signals for east-bound traffic have been designated S S and S from left to right, and the signals for west-bound trafiic have been designated S S and S Since the apparatus at the entrance to each block for each direction of trafiic is the same, it will sufiice to describe the apparatus illustrated for the signal S in Fig. 1A of the drawings, corresponding parts of the apparatus associated with other signals being designated by the same reference character having an exponent corresponding to the exponent of the signal with which it is associated.

Referring to the apparatus associated with signal S each junction between successive blocks is provided with a vibrator, such as vibrator V for signals S and S These vibrators include an electro-magnet i3 and a permanent magnet N-S and two tuned armature reeds M and I4", which reeds may in fact be a single reed having two sets of contacts insulated from each other. Each of these vibrators may, for instance, be of a construction such as shown in Fig. 2 of the patent to Dicke, Patent No. 1,7 68,750, dated July 1, 1930, wherein the vibrator is used as a rectifier. When used in the present signaling system this vibrator may either employ two reeds M or have two sets of contacts l'I-l3 controlled by the same reed, the same electro-magnet and the same permanent magnet.

At the west end entrance of the block X is provided a suitable polarity responsive relay, such as the polar-neutral relay T illustrated. This relay T is connected to the track circuit of the block X through the medium of the right-hand contact 14 of the vibrator V At the same end of this block is provided a transformer T1" which supplies alternating current from a transmission line to the west end of block X, but may also be used for supplying track circuit current to the east end of the block W, although as illustrated a separate transformer Tr has been illustrated for this purpose. This transmission line feeds all of the transformers Tr so that all of the vibrators V operate in synchronisrn, particularly positive or negative polarity to the west end of i the block X during the periods between the connection of the track relay T to this end of the track circuit. This polar-neutral track-relay T is constructed in the usual manner so that its polar contact remains in the last position to 5 which the relay was operated even though the relay is thereafter deenergized, whereas the neutral contact will assume its deenergized position shortly after deenergization of the relay, the neutral armature may however be of the retained type as disclosed in the patent to Field No. 2,180,583. The neutral contacts of these track relays T are in any event suificiently slow dropping so as not to move from their attracted position between the pulses of the pulsating current applied thereto. Each of these track relays T is provided with a track repeater relay TR insofar as repeating the energized or deenergized position of the track relay is concerned. Each signal is also provided with a directional stick relay SR.

Under clear trafiic conditions the track relay T is energized to its right-hand position because pulsating current of positive polarity is applied to the east end of the block X. With the track relay T assuming its right-hand position an energizing circuit, including the front contact I5 and the polar contact H3 in its righthand position, for the green lamp G is closed. Also, with the track relay T energized the track repeater relay TR. is energized through the front contacts I7 of the track relay T Furthermore, with the track relay T and the track repeater relay T normally energized, and with the directional stick relay SR normally deenergized, an energizing circuit which supplies pulsating current of positive polarity to the east end of the block W is intermittently closed by the contact M" of the vibrator V This circuit may be traced from the secondary winding of the transformer Tr through the rectifier +R front contact 23 of the track relay T front contact 2H of the repeater relay TR back contact 22 of the stick relay SR back contact 23 of the stick relay SR through the right-hand contact I4 to the east end of the block W through the track relay at the west end of this block W (not shown) and back to the center tap of the secondary winding of the transformer Tr". Although the vibrator contact l4 only assumes its right-hand position when the right-hand terminal of the secondary winding of the transformer Tr is of positive polarity, so that a pulsating current of positive polarity can only be applied to the circuit just traced even if no rectifier were used, nevertheless the rectifier +R is included in this circuit as an additional check against energizetion of this clear manifesting circuit with current of negative polarity. A similar rectifier R" is provided in the caution circuit for east-bound trafhc in block W, which circuit may be traced as follows: beginning at the left-hand terminal of the secondary winding of transformer T1. rectifier -R", through front contact 22 of stick relay SR back contact 23 of relay SR and vibrator contact M Obviously, if desired, these rectifiers R may be omitted.

Operation Under normal clear traffic conditions all of the track relays T are energized to the right and their associated track repeater relays TR are also energized and all of the directional stick relays SR are deenergized for reasons pointed out above. For this reason all of the track circuits are energized by pulsating current of positive polarity irrespective of whether this current is applied to the east or the west end of the block in question. Let us now assume that there is a train moving from west to east (left to right) and that this train has just entered the block W. This entrance of the train into block W causes deenergization of the track relay T Deenergization of the track relay T causes opening of its front contacts I5 H and. 2G" and causes closure of back contacts I5 25 and 26 The closure of back contact l5" causes illumination of the red lamp R of signal S Since the contacts 25" and 26 are included in circuits that are open at other points no particular function is performed by the closure of these contacts at this time.

The opening of front contacts ll, however, deenergizes the track repeater relay TR and this results in the opening of contact 2i in the track circuit for west bound traffic of block X. This latter circuit having also been broken at the front contact 28 of the track relay T The opening of the west bound track circuit for block X which includes the vibrator contact i i-' as it intermittently assumes its left-hand position, results in deenergization of the track relay '1" for controlling the signal S next in the rear of the signal S, and similarly the dropping of track relay T causes deenergization of the track relay T In other words, all of signals governing trafiic in the opposite (West bound) direction to that of the train under consideration are immediately operated to indicate stop.

As this east-bound train in block W passes the signal S it causes deenergization of the track relay T as a result of which a pick-up circuit is closed for a directional stick relay SR which may be traced from the terminal through back contact 28" of repeater relay TRJ, back contact of track relay T front contact 29 of repeater relay TR, winding of the stick relay SR back contact 3| of the opposing stick relay SR to the other terminal Completion of this circuit picks up the directional stick relay SR which is then stuck up through a stick circuit including back contact 26 of track relay T and stick contact 39 of relay SR After a short time the pick-up circuit just traced is opened at the front contact 29 and a second stick circuit is closed at back contact 32 of the track repeater relay TR The dropping of the track relay T of course opens the circuit heretofore traced for applying pulsating current of positive polarity to the east end of the block W and including front contact 20 of this relay, the picking up of the directional 7 stick relay SR however, now applies pulsating current of negative polarity through the front contact 22 of this stick relay SR and the back contact 23 of the opposing stick relay SR The entrance of this train into the block X performs no particular function at the east end of this block X because the application of energy to the west end of the block X had already been interrupted by the dropping of the track relay T. If this east-bound train passes the signal S it will cause the picking up of the directional stick relay SR in a manner as just explained in connection with the directional stick relay SR As this eastbound train now entirely leaves the block X and enters the block Y pulsating current of negative polarity is applied to the east end of the block X because the stick relay SR is energized as a result of which the track relay T is again energized. It is, however, now energized to its lefthand position.

With the track relay 'I energized to its lefthand position an obvious circuit for the lamp Y of the signal S is closed. Also, energization of the track relay '1 results in energization of relay TR and this interrupts both of the stick circuits for the stick relay SR as well as its pick-up circuit, so that the stick relay SR is again deenergized resulting in the application of pulsating current of positive polarity to the east end of the block W through the same circuit heretofore traced, this circuit being closed irrespective of the polarity of energization of the track relay T As the train under consideration moving an eastwardly direction passes entirely out of the block Y and into the block Z, as shown, pulsating current of negative polarity is applied to the east end of the block Y and pulsating current of positive polarity is applied to the east end of the block X, all in a manner as already explained hereinbefore. With pulsating current of positive polarity again applied to the east end of the block X the track relay T is energized to the right resulting in the reenergization of the green lamp for the signal 8*. In other words, with the train under consideration occupying the block Z, as

shown in the drawings, the signal S has its red lamp illuminated and indicates stop, signal S has its yellow lamp Y illuminated and indicates caution, and the signal S has its green lamp G illuminated and indicates clear. In other words, the circuits as shown in the drawings reflect traffic conditions when the block Z is occupied, as illustrated.

As this east-bound train proceeded from the block W into the block X the track relay T was unshunted and therefore was energized with pulsating current of positive polarity resulting in the illmnination of the green lamp G for the signal S", and similarly as this train proceeded in an eastwardly direction the signals S and S cleared up as the east bound train passed these signals.

The interlock between the directional stick relays SR for governing traffic in opposite directions at the same signal location, which is accomplished through the back contact 3| of one stick re ay included in the wire common to both the pick-up and stick circuit of the other relay, is for the purpose of preventing two stick relays at the same signal location being up at the same time. For instance, if this interlock were not provided the entrance of a second train into a single track section at the west end, for instance, would produce deenergization of all of the opposed track relays between it and the train ahead and this would result in the picking up of the opposing stick relay at the signal location in the rear of such train ahead. For instance, if the first east-bound train occupied block X, the home relay T having picked up as this train left the block W, the entrance of a second train into block W would cause dropping of relay T prior to the dropping of relay TR and would result in picking up of stick relay SR". The provision of the interlocking contact 3|, however, prevents such undesirable picking up of a directional stick relay.

The applicants have thus provided a signaling system of the absolute-permissive-block type in which each block is provided with a double track circuit, so to speak, in which currents of distinctive characters are applied to opposite ends of the track circuit of such block alternately and in which these distinctive characters of current reflect through their track relays the conditions of traffic in advance of the associated signals the end of the block where the current is applied being considered the exit end of such block. The proposed system illustrated therefore aifords the usual absolute-permissive-block protection, which allows following train to follow each other spaced by braking distance and which absolutely blocks the entrance of a train into a single track section in an opposite direction to a train already occupying such block, and accomplishes these functions without the employment of line wires and without the employment of coding apparatus and decoding or code deciphering apparatus.

Having thiw shown and described a single embodiment of the present invention it should be understood that the particular embodiment of the invention illustrated has been selected to facilitate disclosure of the principles of the invention and its mode of operation and not merely to show one form the invention may take. For. instance, it is readily understood that staggered signals may be used instead of opposite signals, and it should also be understood that other changes, modifications and additions may be made within the scope of the present invention and without departing therefrom, except as demandecl by the scope of the following claims.

What we claim as new is:

1. Trackway apparatus for absolute-permissive-block wayside or cab signaling systems for railroads; the combination with a single track stretch divided into track sections by insulating joints; a common source of alternating current available at each junction between adjacent sections; mechanism including a double throw electro-magnetically operated contact operated from said alternating current source to close alternate contacts during alternate half waves of a cycle of alternating current; means at the exit end of each section, for a particular direction of trafiic, including a contact of the mechanism at said junction for applying pulsating current by applying a half wave of either positive or negative polarity during the first half of a cycle of said alternating current to such exit end; means at the exit end of each section, for the opposite direction of trafiic, including a contact of the mechanism at such junction for applying pulsating current by applying a half wave of either positive or negative polarity during the second half of a cycle of said alternating current to such exit end; a polarized track relay connected across the rails at each end of each track section, commutating means for each track relay including a contact of the mechanism at that junction for closing the circuit for such track relay only when impulses of the pulsating current applied to the other end of the same section by the next mechanism in advance are present; apparatus controlled by said polarized track relays efiective upon movement of a train into said stretch to cause by the shunting of the rails of the first section of said stretch the removal of the pulsating current from the entrance end, for that direction of movement, from all of the remaining sections of said stretch, and to further cause the application of pulsating current to the exit end of the section in the rear of a section occupied by such train of a reverse polarity of that of the pulsating current applied to the exit end of a section under clear trailic conditions.

2. In combination, a section of railway track divided from adjacent track by insulating joints; a common source of alternating current available at both ends of said section, two track relays, an electro-magnetic vibratory contact at each end of said section said contacts being vibrated by alternating current from said common source and connecting the ends of said track circuit to two circuit branches during each cycle of said alternating current, the branch first connected in a cycle for one end applying a source of current of one or another polarity to that end and the first connected branch for the other end connecting one of said track relays across the track rails at such other end of said section and the second connected branch for said other end connecting a source of current of one or another polarity to such other end of said section irrespective of the polarity applied at said one end and the second connected branch at said one end connecting the other of said track relays to such one end across the track rails, whereby the track rails of said section form parts of two different polarized track circuits each of which may employ current of either polarity depending on trailic conditions one having a track relay at one end of said section and the other having a track relay at the other end of said section which track circuits exist alternately during each cycle of said alternating current.

3. In combination, a section of track divided by insulating joints into blocks, a signal at the entrance end to each block for each direction of trafiic, contacts at opposite ends of each block operated electro-magnetically in synchronism through a circuit separate from the track rails and extending from one end to the other end of such blocks, means at each end of each block for supplying pulsating current of either positive or negative polarity to the rails of such block, the means at opposite ends of the same block including said contacts and applying such pulsating current alternately, a polarity responsive track relay at each end of each block, means including said contacts for connecting each polarity responsive relay to the end of a block intermittently in synchronism with the intermittent application of pulsating current to the opposite end of such block, a directional stick relay for each signal, and means for controlling each signal by its associated directional stick relay and by its associated track relay.

4. In combination; a section of railway track divided from adjacent track sections by insulating joints; a common source of alternating current available at both ends of said section; means including static rectifiers and transformers at the ends of said section for rendering available pulsating current of positive polarity in which the pulses occur during the first half of each cycle, of positive polarity in which the pulses occur during the second half of each cycle, of negative polarity in which the pulses occur during the first half of each cycle and of negative polarity in which the pulses occur during the second half of each cycle; two polar track relays one at each end of said section; an electro-magnetic vibratory contact at each end of said section said contacts being vibrated by alternating current from said common source and in synchronism with the cycles of said alternating current and connecting the ends of said track circuit alternately to two circuit branches one of which includes a polar relay and the other of which is energized by one of said pulsating currents, the branches at opposite ends of said track section being so connected that when a polar traclc relay is connected at one enda pulsating current is applied to the other end and vice versa, means for selecting the pulsating current applied to a particular end to be of a polarity depending on traflic conditions in the next track section adjacent to that particular end; and signals governed by said polar relays.

5. In combination; a section of railway track divided from adjacent track sections by insulating joints; a common course of alternating current available at both ends of said section; means including static rectifiers and a transformer at one end of said section for rendering available pulsating current of positive polarity in which the pulses occur during the first half of each cycle and also rendering available pulsating current of negative polarity in which the pulses occur during the first half of each cycle; means including static rectifiers and a transformer at the other end of said section for rendering available pulsating current of positive polarity in which the pulses occur during the second half of each cycle and also rendering available pulsating current of negative polarity in which the pulses occur during the second half of each cycle; two polar track relays one at each end of said section; an electro-magnetic vibratory contact at each end of said section said contacts being vibrated by alternating current from Said common source and in synchronism with the cycles of said alternating current and connecting said polar track relays to opposite ends of the rails of said track section alternately and connecting said track rails to a branch circuit when the associated polar track relay is not connected; means for energizing said branch circuit with current of a polarity depending on trafiic conditions in the section adjacent to that end; and railway traflic controlling signals controlled by said polar track relays.

6. In combination; a section of railway track divided from adjacent track sections by insulating joints; a common source of alternating current available at both ends of said section; two polar track relays one at each end of said section;

an electro-magnetic vibratory contact at each end of said section said contacts being vibrated by alternating current from said common source and in synchronism with the cycles of said alternating current and connecting the ends of said track circuit alternately to two circuit branches one of which includes a polar relay and the other of which is energized by one of two currents of opposite polarity, the branches at opposite ends of said track section being so connected to the rails that when a polar track relay is connected to one end of the track circuit one of said two currents is applied to the other end of the track circuit and vice versa, means for applying current of a polarity depending on trafiic conditions in the next track section adjacent to that particular end; and signals governed by said polar relays.

7. In combination; a section of railway track divided from adjacent track sections by insulating joints; a common source of alternating current available at both ends of said section; means for producing pulsating current of positive polarity in which the pulses occur during the first half of each cycle and also producing pulsating current of negative polarity in which the pulses occur during the first half of each cycle; means at the other end of said section for producing pulsating current of positive polarity in which the pulses occur during the second half of each cycle and also producing pulsating current of negative polarity in which the pulses occur during the second half of each cycle; two polar track relays one at each end of said section; two branch circuits one at each end of said section; an electromagnetic vibratory contact at each end of said section said contacts being vibrated by alternating current from said common source and in synchronism with the cycles of said alternating current and connecting said polar track relays to opposite ends of the rails of said track section alternately and connecting said branch circuits to the track rails alternately, each branch circuit being connected to the track rails when the associated polar track relay is not connected; means for energizing said branch circuits with current of a polarity depending on traffic conditions in the section adjacent to that end; and railway traffic controlling signals controlled by said polar track relays.

8. In combination; a section of railway track divided from adjacent track sections by insulating joints; a common source of alternating current available at both ends of said section; two polar track relays one at each end of said section; an electro-magnetic vibratory contact at each end of said section said contacts being vibrated by alternating current from said common source and in synchronism with the cycles of said alternating current and connecting said polar track relays to opposite ends of the rails of said track section alternately and connecting said track rails to a branch circuit when the associated polar track relay is not connected; means for energizing said branch circuits with current of a polarity depending on traflic conditions in the section adjacent to that end; and railway traffic controlling signals controlled by said polar track relays.

9. In combination, a section of railway track divided from adjacent track by insulating joints, a pair of line wires extending along said section, a source of current of normal polarity and a source of current of reverse polarity at each end of said section, a polar track relay at each end of said section, double-throw contacts at one end of said section for alternately connecting the track relay at that end and one or the other of said sources of current at that end to the track rails of said section at that end, doublethrow contacts at the other end of said section operated in synchronism with said first mentioned double-throw contacts through the medium of said pair of line wires to connect the polar track relay at said other end and one or the other of said sources of current at said other end to the track rails at said other end alternately in such a manner that a track relay is connected to one end of the track rails of said track section when one of the Sources of current is connected to the rails at the other end of said track section, means for selecting said sources of current in accordance with trafiic conditions in the adjacent track section, and signals controlled by said polar track relays.

OSCAR H. DICKE. FOREST B. HITCHCOCK. 

